A 5-V 125-kHz Fourth-Order Continuous-Time Sigma-Delta Modulator in 130-nm BCD Technology

High-resolution sigma-delta modulators (SDM) are widely adopted in the audio band. However, to achieve similar resolution in a higher bandwidth is a challenging task. In this work, we present the design of a fourth-order continuous-time sigma-delta modulator with high-resolution and signal bandwidth of 125 kHz. The proposed circuit is designed at schematic-level in a 130-nm BCD process and operates with a supply voltage of 5 V. The modulator total power consumption is 19.87 µW. The simulated peak signal-to-noise ratio (SNR) and signal-to-noise-and-distortion ratio (SNDR) considering noise are 97.01 and 96.93 dB, respectively. The achieved dynamic range (DR) is 103.2 dB, leading to a Schreier figure-of-merit of 171.1 dB, which is comparable to the state-of-the-art, although a higher supply voltage is used.